How Drunk You Feel Depends on Who You're With

Do you know when you've had enough to drink? That depends on where you are and who you're with, according to a new study published in the journal BMC Public Health.

In an atmosphere with many other individuals consuming alcohol, drinkers are more likely to underestimate how much they've had to drink, their own levels of intoxication, and the health implications of their consumption. In an environment with predominantly sober individuals, drinkers tend to feel more at risk when they were inebriated.

For their study, researchers at Cardiff University in the United Kingdom measured the breath alcohol concentrations of 1,862 drinkers who were on average 27 years old. Tests were administered between 8 p.m. and 3 a.m. on Friday and Saturday nights in four areas with a high number of locations that served alcohol.

A subset of participants were asked a series of questions to determine how they viewed their level of inebriation and the long terms risks of their behavior. These questions included:

Their impressions were notably influenced by their environments, a finding the researchers hope will inform harm-reduction strategies around alcohol consumption.

"Researchers have historically worked under the assumption that those who drink the most alcohol incorrectly 'imagine' everyone else also drinks to excess," co-author Simon Moore said in a statement. "It turns out that irrespective of how much someone has drunk, if they observe others who are more drunk than they are, they feel less at risk from drinking more."

Even without environmental influences, self-reporting levels of inebriation has always been tricky. In fact even observers trained to identify levels of intoxication struggle for consistent reporting, according to a 2009 study published in the journal Alcoholism: Clinical & Experimental Research.

Many different factors contribute to the identification of "intoxication," and even courts have different standards of "obvious intoxication" versus "visible intoxication." Someone who is obviously intoxicated may have had a high number of drinks, but not showing signs of visible intoxication, such as slurred speech or staggering.

Whenever there is uncertainty about whether someone is drunk, in order to avoid the potential consequences of driving impaired or drinking to excess, the best advice is to play it safe. Call it a night. Catch a ride. Get some sleep.